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P0638 Error code and EPC Light


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Screenshot_20161025-210325_zpsvjopecrf.p

So i have this fault, which is to do with the throttle body. The issue i have is that that the trottle body is brand new, and has been fitted to a recently fitted engine. 

Twice in the past three days, the EPC light has come on and this code has come up, and the car has gone into limp mode, even though it is a brand new throttle body. When the throttle body was fitted, it was adjusted with VagCom by the mechanic, and the code came straight back up, but it drove fine. 

Does anyone have any ideas as to what this could be? Because its driving me insane worrying about when ill lose power next!  

Thanks in advance,

Myles. 

Edited by myles983
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Thanks for the reply Sausage.

I assume hes done the TBA also. 

How difficult would it be to wire a new plug in ? And how would i go about diagnosing a faulty wire? Multimeter and a wiring diagram with the voltages and impedance on it ? 

Oh and as soon as the recovery truck dropped me off, Loopy was fine. No EPC light and running normally....

Edited by myles983
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Pull plug off look for green fluff or signs of corrosion and / or baggy contacts, plug and unplug a few times to scrape the contacts and get a good contact and check the wires for a few inches back from the plug as well for damage, feel the wires for breaks and if they are stiff and non bendy they are probably corroded internally. 

You might want to try vagcom and see if it shows other codes as some other diagnostic stuff doesnt pick everything up. Google for that code on Lupo and it should come up with something to go on.

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Ok, ill try cleaning off the contacts. I looked at the wires last night, and theyve got a plastic shroud on them, which means its not as easy to check them without removing the shroud. 

Where does the cable from the throttle body plug into ? In the event it still plays up, couldnt i just buy that section of cables between the throttle body and wherever and use that? 

As for searching for anything related to a Lupo, i tried in vain last night and only came across situations that were to different to my own to be of any use. 

 

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£5 lead a spare laptop and VCDS lite  (can be unlocked to registered version by paying or by a google search) is all you need.

I doubt there's any need to dismember the plug, it should be fairly obvious if the contacts are in poor condition.

Has the recently fitted engine been running fine prior to this and why was the throttle body replaced? What codes were you getting?

if you get VCDS (vag com) up and running you can do the TB alignment yourself if needed and it will probably show up other codes too plus do loads of other stuff with it.

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4 hours ago, Sausage said:

£5 lead a spare laptop and VCDS lite  (can be unlocked to registered version by paying or by a google search) is all you need.

I doubt there's any need to dismember the plug, it should be fairly obvious if the contacts are in poor condition.

Has the recently fitted engine been running fine prior to this and why was the throttle body replaced? What codes were you getting?

if you get VCDS (vag com) up and running you can do the TB alignment yourself if needed and it will probably show up other codes too plus do loads of other stuff with it.

Ok, will look into it. Thank you very much. The engine was running fine as far as i know, and the new throttle body was due to misinformation: i was told that the original throttle body was broken after a headgasket replacement, when in actual fact it hasnt been aligned and so wouldnt have worked anyway. So i bought a new one and obviously, it still didnt work. So with the engine swap, the mechanic put the new throttle body on seeing as i had it. 

 

Edited by myles983
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